Module opcodes 

Opcode definitions and instruction encoding/decoding for the Lua 5.4 VM.

Ports src/lopcodes.c (the luaP_opmodes table) and src/lopcodes.h (the OpCode/OpMode enums, field-size constants, and instruction accessor macros). Per PORTING.md §1, headers merge into their consuming .rs.

C source preserved inline as `

Structs

Instruction

A single Lua bytecode instruction (unsigned 32-bit word).

Enums

OpCode

All opcodes for the Lua 5.4 virtual machine.

OpMode

Instruction addressing mode.

Constants

LFIELDS_PER_FLUSH

Number of list items to accumulate before a SETLIST instruction.

MAXARG_A

MAXARG_AX

MAXARG_B

MAXARG_BX

MAXARG_C

MAXARG_S_J

MAXINDEXRK

Maximum RK index (for debugging only).

NO_REG

Sentinel “no register” value that fits in 8 bits.

NUM_OPCODES

Total number of opcodes.

OFFSET_S_BX

OFFSET_S_C

OFFSET_S_J

POS_A

POS_AX

POS_B

POS_BX

POS_C

POS_K

POS_OP

POS_S_J

SIZE_A

SIZE_AX

SIZE_B

SIZE_BX

SIZE_C

SIZE_OP

SIZE_S_J

Functions

get_op_mode

Extract the OpMode for an opcode.

int_to_s_c

Encode a signed integer into an unsigned C-field value.

s_c_to_int

Decode a C-field unsigned value to a signed integer.

test_a_mode

True if this opcode writes to register A.

test_it_mode

True if this opcode uses L->top as set by the previous instruction (B == 0 case).

test_mm_mode

True if this opcode is a metamethod call.

test_ot_mode

True if this opcode sets L->top for the next instruction (C == 0 case).

test_t_mode

True if this opcode is a test (the next instruction must be a jump).